Mechanism for propelling vehicles



A.BOYD. MECHANISM FOR PROPELLING VEHICLES.

APPLICATLQN FILED FEB. 4| l9l 9.

Patented Nov. 25, 1919.

3 SHEETS-SHEET 1.

A. BOYD.

MECHANISM FOR PROPELLING VEHICLES.

APPLICATION FILED FEB. 4| ISIQ.

0m 1 9 1 5 2 V 0 N d 6 t H m a P BOYD. MECHANISM FOR PROPELIING VEHICLES.

APPLICATION FILED FEB. 4, I919.

Patented Nov. 25, 1919.

3 SHEETS-SHEET 3.

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MECHANISM FOR PROPELLING VEHICLES.

Specification of Letters Patent.

Patented Nov. 25, 1919.

Application filed February 4, 1919. Serial No. 274,994.

1 '0 all whom it may concern:

Be it known that I, ARTHUR Born, a subject of the King of Great Britain and Ireland, residing at 7 Queensberry avenue, Vest Hartlepool, in the county of Durham, England, have invented certain new and useful Improvements in Mechanism for Propelling Vehicles, of which the following 1s a specification. V

This invention relates tomechanism for the propulsion of bicycles of the kind designed to enable increased leverage to be obtained during the driving stroke of each crank and also to enable an effective driving leverage to be obtained by each pedal 218 113 passes through the top dead center before the leverage exerted by the other pedal becomes ineffective, the invention representing a further development of the mechanism described in United States Patent No.

1126947granted to me.

The object of the present improvement is to simplify the mechanism and thus to reduce the weight and cost of production and to render the gear applicable to existing machines.

The mechanism of this invention comprises a driving crank and crank pin, a pedal elongated toward the front and mounted on the crank pin, a clutch rod or controlling rod having a considerably reduced angular velocity compared with that of the crank, journaled-at one end upon the crank pin, the other end of the clutch rod being constrained by any suitable means to move in a-predetermined path, and means for causing the pedal to engage with the clutch rod as the-crank pin approaches its top center and'makes a driving downward stroke, and to partially disengage therefrom during the upward idle stroke of the crank. But it is to be understood that the invention includes modifications in certain details of the improved mechanism as willhereinafter be explained. I

In order that the invention may be clearly understood the mechanism relating thereto will now be described with the aidof the accompanying drawings in which Flgure l is a side view 'of a bicycle fitted with the improved propelling mechanism; Fig. 2 is a plan view of the said mechanism; Fig. 3

is a diagram designed to explain the me chanical advantage obtained by the use of the improved mechanism; Figs. a, 5 and 6 illustrate details upon an enlarged scale.

As theimproved mechanism is applied to each crank and pedal in precisely the same way, it will be sufiicient to describe the apto prevent the foot from slipping forward and, in the form shown, a clutch rod 8 journaled atone end upon the boss of the pedal mounted on the said crank pin 3 and situated between the pedal oand the: outer face of the crank 1, the clutch rod 8 being formed for this purpose with an enlarged lower end terminating in, orhavingattached thereto,

7 a ring or ball race 9 concentric with the crank pin 3. The small or upper end of the clutch rod 8 terminates in a ring or ball race 10 adapted to work between the jaws of the forked end 11 of a radius rod 12 to which the said clutch rod is pivotally connected by a pin 13 passing through holes in the jaws of the forked end 11 of the radius rod and through the ring 10 at the small upper end of the clutch rod 8; the other end of the radius rod 12 is preferably forked (see Figs. 2 and 6) and pivoted at 14 upon a projection 15 fitted with a socket adapted to be detachably fixed t0 the corresponding side of the back fork of the machine.

On the inner side of the heel portion 7 of the pedal 5 an inwardly extending projection 16 is provided, so arranged as to clear the crank arm 1 as this revolves but adapted to engage an outwardly projecting pin 17 arranged for this purpose upon the clutch rod 8 every time the crank arm 1 approaches its top center. As an alternative arrangement, clutch projections 18 (Figs. 4 and 5) may be provided upon the inner side of the pedal 5 adapted to engage counterpart clutch projections 19 provided upon rim 9 of the lower end of the clutch rod. 8. The effect of this engagement between the projection 16 on the pedal. 5 and the pin '17 or the clutch projections 18 and 19 is that the pedal is locked to the clutch center as described above, the lateralpro jection 16 011 the pedal 5 is in contact with the pin 17 on the clutch rod 8 and the pedal. iS' QOIlSGQHQlliZlY locked to the clutch rod,

my 00 55 to ww; these full lines show the inclination the pedal would have it constrained to move as one integral piece v th theclutch rod, or in permanent contact iv'ith the "pin 17011 th'eclutch rod.

I The curyesinthe diagram are found as pressing with the foot; on the "front" edge 5 tained until the crank has passed beyond the lower dead center; 117"W1ll'b6 seen "that "same time the other crank 2' and its pedal 6 locked tothe corresponding clutch rod will {have come into'a position of effective leverage. -"As the cr'ankl rises on its idle stroke 2055" autoniati- *the'projection 16 on the pedal can d-isengages from the pin 17 'on'the clutclifrod 8'1'1ntil the'er'ank approaches-its if Center when thef p rojection;16 'on' the pedal again engages the pin 17' on the clutch' when" the crank-reaches its bottom center (Fig.- 1) there 'stlll remains 'a'certaln amount otlevera'ge'Whereivith the rider can force "rodand'the above cycle is "repeated.

Referring to Fig. 3, V and Hare yerti'cal horizontal center lines respectively: thr ')ugh the? axis of the crank shaft and 1 1' bicycle.

. ot'e'qualdivisions atthepoints a, b, '0', d, .e L to w. The center'li11e*,of'tlie pedal j m; A for the downward or power stroke, and

"Ward stroke. 7 Seine corresponding positions.

' diagonal lines ca 00*. .to um).

I Qne end" oi the clutch rod is carried "*aroundfb'y' the crank pat-the other end is' suitably piyoted to one'en'd of a radius link "Ryorks upon the fixed point 14 as in the fforin f trated infFigs. 1, 2 and 4 to 6.

I When the crankis on the top center the pedal is horizontally disposed at ad and the pedail and rod are now in rigid "contactgthe eXe'rtingfthe i naxiinum force. This angle which the pedal is free toa s su'rneless angle of the part 7 of the pedal the lock is inain 's an'adjustable fixed point on the frame of" from its 'axis to its forward"extreniity is" "indicated by the lines ea; N)", 00 .to

. to 70 the otherend of 'Which' follows :Assu1ning the angular Velocity of the crank to be uniform about its axis and represented by its radius length then the 7 Tak'ng the-position of the cranlcCj' for 'illilstration"; Cj will represent the; velocity theeranli pastthe dead center-{and at the 'yelocity of the extremity of the pedal at j about the center C at that particular instant.

A'curv'e drawntlirongh the points 0 f g [L3 to n -sl1oWs the increase of leverage due to the instantaneous bell cranks p'oWeris applied at theend of the pedal j.

of thejcluteh' rod' ar'e show n 'by' the longitapplying the same force to the original as above and these bellcra nks have a potentialangle (in'res'pect of a downward force) fiv'h'ich increases in relation to the crankas r c v, thecrank revolves on'it's power stroke. Thecrank :p athis diyided i'nto a nuinber 1) As the force is applied'nornial to the pedal (orfarni of-"the instantaneous bell crankithi'sforc'e Will act in the direction of the line j land 'ineet the center line of its effective length of the crank is Cj When the Thiss'hows' anadvantage compared with *cr'ank pin at j .o-rby-lap'plying a'corre'spond- "ingly reduced "r er.-

, a r By drawing. a curve-[through the several points '6 f g h z' n found in this Way foreachpo'sition'of the crank iti'spjossible to I W gildi atedf by the de fte'd rcd a; atthe' fcoininenceinent of;the stroke and by 0 0' mwa a the-Tend off the 7 power I stroke; after :ineasurethe e'fl'ectivej length of the'crank at any c intermediate position. f

In the 1' above 5 described arrangement the 'brojection 16 tn thepedn 5'takes the place I I of tlie', free"wheelchitCh'Qand the clutch rod Tan l be w en th o endfl ein i @011- f1.stantthrouglioutithe downward stroke when I being centeredj -on' the'crank pin takes the place of the ecceiitricand' rod employed in arrangem t" described in the former F patent h'ereina'bo've' referred to, the present arrangement being considerablysimplified Lreliatively towns? former "arrangement trol ofthe olutch rod toc'onimenceanother' power stroke.

'g-ular jnioifeinefit of the pe dal to suit the refquirements of "the fiderf 1 For example, by

v c ,jreasedfwhile moi ing point lt'fa'rther It Wll'l be obseryed'. that during the up" stroke the pedal is alsoshown byfull lines away from the Vertical center V V thesaid range 'can be "diminished. Alse by raising v crank arni"in' the point Tl'ierefore the H I A arroraipg nieansror adjusting the'anif required by the foot; shown approxi the point 14 the pedal at the commencement of the stroke is inclined below the horizontal and by lowering the point 14 the pedal at the commencement of the stroke is inclined above the horizontal without altering the range. Again, by shortening or lengthening the radius rod 12 the angle of the pedal can be altered for commencement of the .stroke and by a combination of these adjustments the most effective position can be obtained Without difficulty.

It is evident that the present invention is not limited to the details hereinabove de scribed as the improved mechanism is susceptible of various modifications of details Without thereby altering the essential characteristics of the mechanism. The outer end of the clutch rod could be controlled by curved or straight guides angularly adjustable and fixed to the frame of the machine, thus dispensing with radius links.

In some cases it may be possible to make the clutch rod and pedal one integral piece, and dispense With any kind of clutch, the outer end being guided in a suitable and adjustable fixed path, the object being to make the gear as simple and direct as possible and at the same time to enable more leverage to be obtained for a given length of crank when traveling up an incline or propelling against Wind resistance. This modification is applicable When no back pedal brake is applied, or when it is not intended to mount the machine from the pedal.

What I claim and desire to secure by Let ters Patent is 1. Mechanism for propelling a bicycle comprising a driving crank, a crank pin secured thereto, a pedal mounted on the crank pin having an elongated front portion, a clutch rod rotatably mounted at one end upon the crank pin axis, means for con straining the other end of the clutch rod to move in a predetermined path, and means for causing the pedal to engage with the clutch rod during one part and to disengage therefrom automatically during another part of a revolution of the crank.

2. Mechanism for propelling a bicycle comprising a driving crank, a crank pin secured thereto, a pedal moimted on the crank pin having an elongated front portion, a clutch rod rotatably mounted at one end upon the crank pin axis, a radius rod pivoted to an adjustably fixed point on the frame of the machine, a pivotal connection between the free end of the clutch rod and of the radius rod, and means for causing the pedal to engage with the clutch rod during the driving stroke of the crank and to disengage therefrom during the idle stroke of the crank.

3. Mechanism for propelling a bicycle comprising a driving crank, a. crank pin secured thereto, a pedal mounted on the crank pin,a clutch rod rotatably mounted at one end upon the crank pin axis, means for constraining the other end of the clutch rod to move in a predetermined path and a lost motion clutch device for clutching the pedal to the clutch rod during a fraction of each driving stroke of the crank.

l. Mechanism for propelling a bicycle comprising a driving crank, a crank pin secured thereto, a pedal mounted on the crank pin, a clutch rod and a pedal formed as one.

integral piece, and means for constraining the other end of the clutch rod to move in a predetermined path.

5. Mechanism for propelling a bicycle comprising a driving crank, a crank pin secured thereto, a pedal mounted on the crank pin, a boss on the pedal, a clutch rod mounted at one end upon the pedal boss, a fixed curved guide of any suitable radius length, including infinity for the other end of the clutch rod secured to the frame of the machine, means for angularly adjusting the fixed guide in the plane of the driving crank, and means for clutching the pedal to the clutch rod.

In Witness whereof I have hereunto signed my name in the presence of two sub- 

